mount_nullfs.c revision 4065 
1/*
2 * Copyright (c) 1992, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software donated to Berkeley by
6 * Jan-Simon Pendry.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38char copyright[] =
39"@(#) Copyright (c) 1992, 1993, 1994\n\
40	The Regents of the University of California.  All rights reserved.\n";
41#endif /* not lint */
42
43#ifndef lint
44static char sccsid[] = "@(#)mount_null.c	8.5 (Berkeley) 3/27/94";
45#endif /* not lint */
46
47#include <sys/param.h>
48#include <sys/mount.h>
49#include <miscfs/nullfs/null.h>
50
51#include <err.h>
52#include <stdio.h>
53#include <unistd.h>
54#include <stdlib.h>
55#include <string.h>
56
57#include "mntopts.h"
58
59struct mntopt mopts[] = {
60	MOPT_STDOPTS,
61	{ NULL }
62};
63
64int	subdir __P((const char *, const char *));
65void	usage __P((void));
66
67int
68main(argc, argv)
69	int argc;
70	char *argv[];
71{
72	struct null_args args;
73	int ch, mntflags;
74	char target[MAXPATHLEN];
75	struct vfsconf *vfc;
76
77	mntflags = 0;
78	while ((ch = getopt(argc, argv, "o:")) != EOF)
79		switch(ch) {
80		case 'o':
81			getmntopts(optarg, mopts, &mntflags, 0);
82			break;
83		case '?':
84		default:
85			usage();
86		}
87	argc -= optind;
88	argv += optind;
89
90	if (argc != 2)
91		usage();
92
93	if (realpath(argv[0], target) == 0)
94		err(1, "%s", target);
95
96	if (subdir(target, argv[1]) || subdir(argv[1], target))
97		errx(1, "%s (%s) and %s are not distinct paths",
98		    argv[0], target, argv[1]);
99
100	args.target = target;
101
102	vfc = getvfsbyname("null");
103	if(!vfc && vfsisloadable("null")) {
104		if(vfsload("null"))
105			err(1, "vfsload(null)");
106		endvfsent();	/* flush cache */
107		vfc = getvfsbyname("null");
108	}
109
110	if (mount(vfc ? vfc->vfc_index : MOUNT_NULL, argv[1], mntflags, &args))
111		err(1, NULL);
112	exit(0);
113}
114
115int
116subdir(p, dir)
117	const char *p;
118	const char *dir;
119{
120	int l;
121
122	l = strlen(dir);
123	if (l <= 1)
124		return (1);
125
126	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
127		return (1);
128
129	return (0);
130}
131
132void
133usage()
134{
135	(void)fprintf(stderr,
136		"usage: mount_null [-o options] target_fs mount_point\n");
137	exit(1);
138}
139